Title: Why Tall Buildings? The Potential of Sustainable Technologies in TallBuildings

Author: Abdel Rahman Elbakheit, King Saud University

Subjects: Architectural/DesignSustainability/Green/Energy

Keywords: Integrated DesignOptimizationSustainabilitySystems

Publication Date: 2012

Original Publication: International Journal of High-Rise Buildings Volume 1 Number 2

Paper Type: 1. Book chapter/Part chapter2. Journal paper3. Conference proceeding4. Unpublished conference paper5. Magazine article6. Unpublished

© Council on Tall Buildings and Urban Habitat / Abdel Rahman Elbakheit

ctbuh.org/papers

International Journal of

High-Rise Buildingswww.ctbuh.org

International Journal of High-Rise Buildings

Vol 1, No 2, June 2012, 117-123

Why Tall Buildings?

The Potential of Sustainable Technologies in Tall Buildings

Abdel Rahman Elbakheit†

College of Architecture and Planning, King Saud University, Riyadh-11574, P.O. Box 57448, Kingdom of Saudi Arabia

Abstract

This paper discusses major strengths of tall buildings that distinguish them as sustainable solutions for the built environment.It sheds light on some of the key attributes of tall buildings as well as materials and technologies that could boost theirperformance environmentally, economically and technically as well as the natural habitats containing them. Tall buildings areportrait as major successful options for accommodating the ever increasing urban world population, with little negative impacton ecologies and environmental habitats worldwide. The role of tall buildings as 'vertical garden sub-cities' mitigating moderncity problems of 'urban heat islands' and sprawling cities is explored. A few building examples as well as city developmentsare presented which represent the new generation of sustainable tall buildings that are setting trends for future projectsincorporating innovations in materials and building systems and designs.

Keywords: Tall Buildings, Sustainable Architectural designs, Integration and optimization of building systems

1. Introduction

The history of tall buildings in north-America from the

late nineteenth century reveals that buildings are a

reflection of the knowledge, technology as well as the

needs of their era (Ali and Armstrong, 2008). Unlike

other building types, tall buildings had evolved very

rapidly in adopting the ever increasing technical solutions

that are in many ways very essential for their existence as

well as operation (i.e., mechanical and electrical lifts,

HVAC systems, lighting, etc. Obviously, this had

developed gradually by realizing the possibilities of

structural solutions for high-rise buildings first (Khan,

1974) then came the other services. In addition to this and

Due to the size of tall buildings, they are by far having

the greatest energy demand and consumption. Buildings

in general consume the greatest share of energy and

carbon emissions. With the residential sector have over

60% and 7% for commercial sector. Whereas as per

square meter consumption commercial buildings consume

greater energy than residential (Yeang, 1999). Therefore

trying to reduce energy use per square meter in high rise

buildings would lead to proper control of energy and

provide bench marking for improvement in performance.

According to M.M. Ali and P.G. Armstrong, a rate of less

than 150-250 KWh/meter square per year would be

acceptable for full mode HVAC high rise in temperate or

equatorial regions.

2. Sustainable Building Design:

Recent developments in the sustainable architectural

building design have been attributed mainly to efforts of

various engineering and scientific attributions. Whereas

the delivery of sustainable architecture where building

design forms the basic fundamental components, has

been undertaken by architects for decades if not century’s

through vernacular architecture and passive architectural

systems. These two distinct trends are manifested in what

we can call smart buildings, intelligent buildings, energy

efficient and sustainable buildings for the former trend

and green architecture, sustainable architecture or passive

driven architecture for the later.

High-rise building can make benefit of both approaches,

with more emphasis on the former trend. Since it depends

mostly on system solutions in structural, mechanical,

electrical, transportation, natural lighting, ventilation and

façade design. Having said that, the ingenuity of the

sustainable architectural design would be expressed in

striking the balance between systems drawn from shared

attributes and the spatial relations drawn from functional,

social or economic requirements. Such comprehensive

design solutions can be seen from Fosters’ design of the

Commerz bank in Frankfurt, where vertical means of

circulation, structures and natural ventilation, day-lighting

and air conditioning are incorporated in a central core

forming an atrium. The plan having a triangular shape,

accommodating two office halls and the third closing side

is an on-floor garden alternating every ninth floor. Façade

curtain walls provide maximum daylight from all around

the building as well as from the central atrium. Supply

†Corresponding author: Abdel Rahman ElbakheitTel: +00966-1-469-6603E-mail: Abdel.Elbakheit@hotmail.com

118 Abdel Rahman Elbakheit | International Journal of High-Rise Buildings

natural ventilation is also drawn through the double skin

façade with heat recovery to exhaust air. These measures

resulted in high efficiency in energy use and lowered the

operating costs considerably. Some other tall buildings

also adopted this notion of the ‘vertical garden’ as in the

National commercial bank in Jeddah designed by Gordon

Bunshaft of SOM architects. Further future success of tall

buildings could rely on mixed-used development for resi-

dence, work, commercial and leisure incorporating the

vertical garden sub-cities.

3. Strategies of Sustainable Design in High-Rise Buildings

No doubt that the corner stone of sustainability is to

reduce or eliminate over exploitation of natural resources

beyond the rate at which they can naturally regenerate.

This obviously can be achieved through efficient use of

resources and indeed energy is the most important here.

A far better step is to rely on true sustainable sources of

power and material, which can be attained from sun rays,

wind power, geothermal power and so forth. Considering

the first two options high-rise buildings provide very high

potential with very large surface area that could be

utilized to harness solar rays for heating, lighting,

buoyancy cooling/ventilation and electricity generation

(Elbakheit, 2008). Wind power with suitable collecting/

converting devices on the other hand has very high

potential due to the acceleration of wind profile with

height in urban areas. Tall buildings by virtue of their

height can benefit from high level of wind speeds in the

mainstream of the atmospheric boundary layer. (Irwin et

al., 2008) However, this high wind may also challenge

the stability of the design and shape of tall buildings due

to vertex shedding and oscillation of the building struc-

ture. Tall buildings response to wind can still be achieved

through proper choice of forms, inertial frequencies,

masses, and damping measures, Fig. 1. This can be

achieved through thorough understanding of the potential

and limitations of the technologies (Irwin, 2009), and the

available resources of a given location. In fact this is an

area of great potential to create and develop systems

serving the main domains of functional, technical and

socio-environmental needs or requirements as well as

sustainability issues.

An example where wind structural loads analysis

further enhanced the architectural solutions of form is

Burj Dubai/Khalifa tower where the structural stability is

achieved through a series of optimizations for (i.e., shape,

Stiffness, mass and damping) as well as the architectural

design requirements, (Adrian smith and Gordon Bill

architects, 2008; Baker et al., 2008). Recently in CTBUH

2011, Y. Tamura has shown that tapering high rise

buildings will result in better stability at the top of tall

buildings, with reservations on some tall building plans.

Further examples for the socio-economic drives shaping

high-rise building design can be experienced in some

design proposals for Chonggae Canal, Seoul, Fig. 2.

Figure 1. Building Forms to improve high rise stability, generate wind energy and maximize natural light from Northelevations and energy Generation form Southern Facades (Dr. Abdel Rahman Elbakheit Tall Buildings' Studio., King SaudUniversity 11-2012).

Figure 2. schematic proposal for Chonggae Canal wereMultiplex buildings are proposed spanning the canal(Jacoby, 2007).

Why Tall Buildings? The Potential of Sustainable Technologies in Tall Buildings 119

Derived by limited available land, developers vie to

generate multiplex types (i.e., high-rise buildings based

on culture and commerce) which are in a continuous state

of redevelopment to create other forms of needed spaces

within them such as leisure or the reincarnation due to

new upgrades within existing activities. This notion for

development of the canal is also accompanied by

relinquished control of access in tall buildings that allow

flow of the commercial areas for instance to occupy

several levels as well as connecting to the street level.

4. Sustainable Systems within Buildings' Fabric

Many available building materials that have been newly

developed to improve the environmental credentials' of

buildings by reducing loads of heating/cooling, lighting

or air conditioning could be used with better efficiencies

in tall buildings as well as to other building types.

However, this is particularly evident due to the cumu-

lative nature of duplicated floors inherent in tall structures

that would lead to increased savings, higher efficiencies

and larger environmental benefits. Among the materials

and technologies we find:

4.1. Innovative insulation materials

Newly developed insulation materials that can provide

higher insulation value and therefore more energy con-

servation and less energy loss add positively to the green

building performance. Some new insulation materials are

transparent or semi-transparent with high insulation value

so they can be used alone as a building material in walls.

Due to their transparency they can provide a level of day

lighting to the interior as well. Thus serving different

functions in an energy efficient way.

4.2. Innovative glazing materials

Much advancement in glazing materials has been

made, whether in improved thermal properties, in terms

of U-values or visual properties in terms of self-tinted and

self cleansing glazing. Generally glazing was one of the

major drives for advancement in the building industry

and to it many of the new concepts of building design are

attributed. Furthermore, many of the passive architectural

systems typical to masonry constructions such as stack

effect and /or displacement ventilation can be enhanced

with the addition of glazing such as in Atriums, glazed

double/multiple facades, Sunspaces or conservatries. New

glazing materials that are combined with photovoltaic

Figure 3(a). Office building natural lighting, open planoffices up, South façade for Natural Lighting and EnergyGeneration (Dr. Abdel Rahman Elbakheit Tall Buildings'Stu., King Saud University 11-2012).

Figure 3(b). Hotel rooms natural lighting by Light shelves, Plans and Section (Dr. Abdel Rahman Elbakheit TallBuildings' Stu., King Saud University 11-2012).

120 Abdel Rahman Elbakheit | International Journal of High-Rise Buildings

cells can acquire both glazing building component func-

tion and electricity generation.

4.3. Natural ventilation and day lighting

Natural ventilation is one of the key principles of green

building design and its importance is emphasized when

employed as a cooling principle in hot or cold climates.

The need for fresh air in interior spaces normally gauged

as air changes per hour according to a specific standard

(i.e., CIBSE or ASHRE standards). However, natural

ventilation as a cooling mechanism can be the major

determinant for building design concepts either in cold or

hot latitudes, The later being of higher importance or

necessity. Buildings can be designed on a passive

ventilation strategy that employs patterns of natural

ventilation without the need for air conditioning. Many of

vernacular architecture examples exist with features such

as wind catchers, underground cooling, fountains, cross

ventilation, internal courtyards and stack effect devices.

Day lighting on the other hand is a field which has also

evolved very considerably in the few past decades. Many

new devices such as light pipes and light shelves were

invented to channel natural light deep into interiors,

which are deprived from normal windows or means of

natural light, Figs. 3(a), 3(b) and 3(c). These devices have

high efficient reflecting surfaces that can transfer over

90% of the natural light through their enclosure to the

place where it is needed.

4.4. Building facades

An example of how both passive architectural designs

or systems and advanced technical systems can be amal-

gamated in buildings, is building envelopes. Building

envelopes or more technically building facades are the

first line of interaction of our buildings with the natural

elements and therefore their design is greatly influenced

by these elements. Hence, greater emphasis is drawn

upon their design with the integration of both active and

passive measures, which are increasingly growing trend

to reduce energy consumption and contribute in energy

generation. Here we will face energy conservation require-

ment, which normally means resort to tighter u-values of

the building fabrics, accompanied with simple passive

design measures. While exploiting the elements is usually

intended towards harnessing the energy contained in them

as a source of renewable energy. Increasingly and as a

result of these concepts more trends on building facades

emerged. This is manifested by designing facades that

incorporate most of the building requirement for solar

shading, heating, thermal insulation, cooling or even

energy production. This is done through using several

devices controlled through sensors and building

management systems. Tall Buildings with large façade

areas would be more favorable for adopting these

technologies and more likely to have a large resource to

be utilized or harnessed specially in energy production.

(i.e., solar or wind energy).

4.5. Smart services and controls

One of the recent development in building automation

services and networks is the development of monitoring

Figure 3(c). Hotel main Entrance View. (Dr. Abdel Rahman Elbakheit Tall Buildings' Stu., King Saud University 11-2012).

Figure 4. Endowment project of King Abdul-Aziz in Mecca,Saudi Arabia.

Why Tall Buildings? The Potential of Sustainable Technologies in Tall Buildings 121

station for all building services. Although it is in its

infancy (i.e., few manufacturing and providing companies

for it), it has great potential for managing, controlling,

optimizing and monitoring building services especially

for Hugh developments and/or tall buildings. Furthermore,

with the introduction of internet wireless communication

it could be very easily to control all electric lighting for

instance within the hole development to cope with the

level of natural light available from a single station,

which can even be at a very remote location. This is also

true to other services, thus providing hugh cuts in initial

costs for wiring for instance, as well as in operation,

maintenance and monitoring costs, etc.. An example of

such a building or development that incorporates smart

services and combines both the size as well as the height

(i.e., 550 m high) is the endowment project of King

Abdul-Aziz in Mecca, Saudi-Arabia, Fig. 4. It's a devel-

opment that consist of a large podium (i.e.,13-storey)

topped by 7-towers with a total built up area of one

million and a half square meter on less than 35000 meter

square. It has 6-residential towers, a 5-stars hotel, a

convention center, a shopping center and a multi-storey

car park. All lighting fixtures, air-conditioning, telephone,

TVs, and doors of rooms are controlled from a single

monitoring station/board as well as billing. Thanks to an

IP network that was the backbone for this installation.

5. Indices of Environmental Performance

In the past two decades, new building standards or

regulations in many parts of the world have been adopted

(i.e., LEED from the United states green building council

USGBC, BREEM from the UK Building Research

Establishment BRE, etc.) to gauge the physical properties

of building materials against the environmental

performance inside buildings and ultimately against the

global environmental well being. These indices are based

on typical code of compliant that defines the standard that

need to be met for a given set of criteria. However, good

they may be, according to Olgyay and Herdt 2004; they

lack an ecological derived base line, as to what degree

they affect the natural ecology they are erected in. These

two researchers suggested a new system to gauge the

ecological services criteria as an environmental assess-

ment of the construction called ‘index of building sustain-

ability’ (IBS) coupled with another gauging the efficiency

of Operation of the building called index of efficiency

sustainability (IES). One of the major advocated of this

process is the design towards using limited land and

therefore densification of the urban setting into high-rise

buildings. Thus choosing to build high-rise becomes the

sustainable option to limit land exploitation.

This notion of concentration of development into high-

rise buildings may find a further reinforcement when

considering other concerns within the micro-climates of

urban terrain known as Urban Heat Islands or UHI’s. The

prime contributor to this phenomenon is the use of

construction materials that retains heat in urban areas,

thus raising their temperatures by around 10 degrees

compared to rural areas, especially night time. Other

factors could contribute to this phenomenon; however,

they are of a lesser magnitude, such as the anthropogenic

activities within urban areas. Bioclimatic Tall buildings in

general and especially those with vertical garden courts

are more prone for less land in the urban-escape

compared to their height. This would reduce the land area

that is susceptible for heat accumulation and in the same

time maximizing the vertical contact with the atmos-

pheric boundary layer and therefore allow for better heat

dissipation to the air. Furthermore thermal sun rays would

be less concentrated on vertical surfaces compared to

horizontal stratus. Vertical gardens, roof gardens or heavy

vegetations within tall buildings would improve the

environmental credentials of tall buildings far better in

this respect as they can eradicate the effect of heat islands

either for an urban setting or a localized micro to meso

climate.

6. The Need for High Rise Buildings

According to the United Nations report in 2001, it is

expected that by 2030 the majority of the world

population will be concentrated in urban areas. This is

Figure 5. development master plan for Riyadh spanning50-75 kilometers radiuses from the center (Courtesy ofRiyadh municipality). Figure 6. Panoramic view of Riyadh City Center.

122 Abdel Rahman Elbakheit | International Journal of High-Rise Buildings

particularly evident in developing countries; major cities

are susceptible for mass migrations from rural areas in the

search for better jobs, services and quality of life. This

poses extra pressure on the natural resources and could be

detrimental if appropriate measures are not implemented.

Bioclimatic tall buildings could provide a sustainable

option for accommodating this unprecedented growth of

population in urban settings worldwide. A good example

in this regard is Riyadh city, capital of Saudi Arabia.

Since 1955 the city adopted an ambitious plan to

expand the city both qualitative and quantitative develop-

ment backed by the economic boom of the oil industry in

the kingdom. This is reflected in the city expanding from

less than a kilometer in radius to 50-75 kilometers of

development, Fig. 5.

Although the city center has a more cosmopolitan

presence of tall buildings resembling those of world class

cities Fig. 6, it realized that better management of the

available resources could be achieved by erecting Sub

centers to solve problems of traffic congestions, city

sprawling and costly long term servicing to infrastruc-

tures. If sustainable tall buildings are to be realized in

these sub-centers this would help to preserve the natural

environment, Fig. 7 and provide an efficient way to deli-

ver the right accommodation and services to the ever

increasing population of the city.

7. Conclusions

Although the initiation and development of tall

buildings was pertained to developed nations, High rise

buildings constitute a solution of great potential when

considering sustainable development of cities and urban

tissues worldwide. They provide densification of the built

environment that otherwise could lead to large exploit-

ation of valuable land or even worse a sprawling growth.

High-rise buildings would enhance the ecological base-

line by reducing exploited land for development. They

could also have significant ramifications to reduce heat

islands, a phenomenon in modern cites by allowing for

more land for greeneries that could have otherwise be

used for built developments. Sustainable technologies

would benefit from the inherent height of tall buildings in

ways that could boost their performance in providing

sustainable sources of energy within urban settings. Tall

buildings could be erected with Sustainable materials and

techniques that preserve the natural habitats of urban set-

tings and provide an efficient utilization to the embodied

energy in them. Possibly hugh environmental benefits can

be attained by virtue of the cumulative nature of duplicate

floors inherent in tall structures that would lead to

increased savings and larger environmental benefits, when

choosing energy efficient systems and sustainable

building materials.

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